pkg-perl: fix build of perl XS packages

Set OPTIMIZE in order to avoid the use of the host $Config{optimize} value
which could cause breakage when cross-compiling for the target.

See discussion in http://lists.busybox.net/pipermail/buildroot/2014-August/104129.html

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
perl: skip some tests which need the toolchain
perl: skip one test for DynaLoader
perl: check date in harness
perl: build with host-qemu
pkg-perl: with qemu
qemu: bump to version 1.7.0
perl: bump version to 5.19.7
perl: bump to version 5.19.8
qemu: bump to version 2.0.0
perl: bump to version 5.19.11

needs linaro 2013.05
(pb in ccsymbols with 2013.11)
perl: bump to version 5.20.0
perl: bump to version 5.21.2
qemu: bump to version 2.1.0